Nur al-Din had long sought to intervene in Egypt especially after missing his opportunity when Tala ibn Ruzzik successfully brought the country under control, blocking his ambitions for nearly a decade. Thus, Nur al-Din closely watched the events of 1163 with his reliable general Shirkuh waiting for an appropriate opportunity to bring the country under his control.

In 1164, Nur al-Din dispatched Shirkuh to lead an expeditionary force to prevent the Crusaders from establishing a strong presence in an increasingly anarchic Egypt. Shirkuh enlisted Ayyub's son, Saladin, as an officer under his command. They successfully drove out Dirgham, the vizier of Egypt, and reinstated his predecessor Shawar. After being reinstated, Shawar ordered Shirkuh to withdraw his forces from Egypt, but Shirkuh refused, claiming it was Nur al-Din's will that he remain. Over the course of several years, Shirkuh and Saladin defeated the combined forces of the Crusaders and Shawar's troops, first at Bilbais, then at a site near Giza, and in Alexandria, where Saladin would stay to protect while Shirkuh pursued Crusader forces in Lower Egypt.